Recently, the task of arranging electronic components on a printed circuit board is carried out by computer assisted design (CAD).
In the meantime, the calorific value as well as the power consumption of an IC is on the increase. There is also an increase of thermal density owing to high-density packaging of components. As a result, the heat of the main IC has an adverse effect of, for example, breaking down neighboring ICs and components. A thermal analysis is therefore needed to know the calorific value in advance.
Jpn. Pat. Appln. KOKAI Publication No. 5-327296 has disclosed a technique for calculating an ambient temperature every arrangement of a component, temporarily arranging components that have not been arranged yet in order to calculate a temperature so that the components that have been already arranged are also included, and deciding the arrangement if the temperature is an allowable temperature.
On the other hand, when a thermal analysis is conducted for a printed circuit board having a great number of electronic components arranged thereon, a considerable amount of time may be taken or the thermal analysis may not be conducted normally.
At the final stage of the arrangement task according to the technique disclosed in the above-mentioned document, a great number of electronic components are arranged on the printed circuit board. Hence, a considerable amount of time is taken before the end of the arrangement task because the time-consuming thermal analysis is conducted every arrangement of a component.